A native of the Eastern Mediterranean, kale has been cultivated for thousands of years. Even the ancient Greeks got in on the action; curly-leaved cabbage was prevalent in the 4th century BC.
Cabbage's favorite cousin, kale spread to western Europe in the 13th century, eventually making its way to North America in the 19th century. Easy and inexpensive to grow and undeniably nutritious, it's little wonder this go-to vegetable popularity has stood the test of time.
Kale grows successfully both indoors and out, with an ideal pH of 6.5 to 6.8. It can handle up to 7.5, however.
In the garden, it can be planted three to five weeks before the spring frost ends, but it's better suited for autumn's cool temperatures. Aim for six to eight weeks before the frost, arranging plants in traditional or raised beds.
Inside, place your plants on a sunny window ledge, ensuring that they receive ample light. A regular pot with a drainage hole works perfectly, while a humidity dome boosts germination and overall moisture.
Kale doesn't require significant space, making it an easy crop to cultivate. Indoors, plants should be spaced eight to twelve inches apart, or simply potted on their own. Outdoors, standard 12" x 12" distancing ensures that each plant gets suitable sunshine, fertilizer, and water while giving leaves space to stretch out.
Kale is one of the few plants that thrive in the shade, flourishing in hardiness zones eight, nine, and 10, which encompasses the Pacific Northwest, most of the South, desert states such as Arizona, Nevada, Utah, and New Mexico, and even the hottest, most tropical parts of California and Florida. While some plants require six to eight hours of sunlight, kale can often prosper with just a few hours every day.
Consistent watering is a must-do to keep your kale crop growing strong. Aim for one to 1.5 inches of water every week — the plants should be moist at least an inch into the soil. Feeding is equally vital; use continuous-release plant food and mulch to keep plants cool and aid moisture retention. Wilted leaves cause kale to dry out and die off, so stay on top of this step.
Your kale plants will attract a wide range of pests, so be on the lookout. Beet armyworms are caterpillars that leave behind hole-filled, skeletonized leaves. Specific treatment products like Bt work wonders.
Cabbageworms leave behind those same chewed leaves, as do cabbage loopers and flea beetles. Cabbage aphids, while destructive, can be eliminated with insecticidal soap. Quickly prune any infected leaves to reduce the chance of spreading.
Kale has a reputation for being pretty hardy, but it's still susceptible to disease. Bacterial leaf spot spreads from splashing water, resulting in yellowed leaves. Black rot also infects leaves, turning them black with dull blotches. Both diseases can be deadly, so prioritize prevention through fertilization, maintaining good airflow, eliminating weeds, and regular inspections.
Fungal diseases are rare in kale, but they can be devastating. Alternaria leaf spot causes dark lesions that can quickly destroy your crop. Keep the leaves dry to reduce the risk, follow the proper prevention steps, and consider using biofungicides.
Kale requires nutrient-rich soil throughout its growth cycle, so it's best to confirm the pH level before you plant. Need to increase the pH? Mix in a nitrogen-rich compost. Blood meal, a water-soluble liquid fertilizer, is another excellent option. Prepare for a thriving crop by applying fertilizer throughout the planting process.
Regrowing kale is completely possible when you use cuttings, and all it takes is three simple steps. First, snip off the top three inches of the bud, including the leaves. Next, dip the stem in rooting hormone to boost the new plant's growth. After it's been cut and dipped, plan the stem directly into your compost pot, ensuring that it receives a plenty of nutrients right away.
Once leaves are the size of your hand, you're ready to harvest your kale. Start with the oldest leaves at the lowest part of the plant, avoiding the terminal bud at the top center; this keeps your kale growing strong. Pick a fistful every harvest, discarding any yellowed leaves. Smaller, more tender leaves are useful for salads, while larger ones can be cooked like spinach.
Want more from every harvest? Extend the growing cycle by keeping kale out of the cold. Row covers work well, helping plants grow continuously into early winter. Kale will grow until temperatures hit 20°F, so you'll have plenty to last through the season.
Once your kale's ready to harvest, you'll enjoy a heaping plate of health benefits. One of the most nutrient-dense foods on earth, kale is packed with powerful antioxidants, flavonoids, and polyphenols, which help counteract free radical damage, turn back the clock on aging, and reduce your risk for cancer and other diseases.
Its low calorie count aids weight loss, while bile acid sequestrants help lower cholesterol levels, reducing your risk of heart disease. Vitamins A and C synthesize collagen, protect cells, and boost your immune system. One of the top sources of vitamin K, kale also aids blood clotting and lowers osteoporosis risk.